Solar panels

[mango]

Can anyone recommend a supplier of reasonably good quality and robust solar panels at an affordable price.

 

The plan is to use them to offset the drain caused by a medium sized 12 volt fridge. I have seen recommendations for using a regulator to avoid overcharging batteries by solar panels, but I assume that the fridge would be more than sufficient to avoid this problem.

 

Assuming that the boat spends more time up north rather than down south, how many months a year are solar panels likely to produce a useful output?

 

Cheers.

[valrene9600]

If you fit a panel to keep up with the fridge you might find it will cook your batteries without a regulator. Why on earth would you risk it.

Even if you fitted a small one that kept up in sunshine come winter it won`t and your back to square one with flat batteries.

Regulator for sure.

 

Edited August 28, 2013 by valrene9600

[blodger]

Solar panels don't run at 12/23/14 volts but 18/22.5 hence the need for the itermediary controller the more expensive of which MPPT are converters with some wizadry to give you 25% more than the cheaper MPW ones.

 

Folk will recommend 'quality' branded ones at price beyond that which I would pay. Cheapo Chinese ones on EBay or even second hand ones will do the job at about 0.50p per watt.

 

I used to reckon that two 55 watt panels ran my old fridge in the summer; No need for it in the winter.

 

Considerations are how much roof space you want to give them and what pay back time you are aiming for. I prefer panels up to 100 watt, 12v nominal, that I have added too over time and, that I can hop scotch over when single handing at locks etc.

 

There are lots of other considerations but not worth getting in to if you are just trying to obviate the fridge load using the batts

[bottle]

Can anyone recommend a supplier of reasonably good quality and robust solar panels at an affordable price.

 

Sorry you cannot have all three

 

The plan is to use them to offset the drain caused by a medium sized 12 volt fridge. I have seen recommendations for using a regulator to avoid overcharging batteries by solar panels, but I assume that the fridge would be more than sufficient to avoid this problem.

 

You assume wrong, sorry, nominal 12v panels actually are in the regionof 17.5v and if you connected direct to your batterries they would gas. (boil)

 

You will need a 'controller' either PWM cheap or MPPT dearer.

 

The fridge will not be running continuously (assuming it is a compressor type)

 

Assuming that the boat spends more time up north rather than down south, how many months a year are solar panels likely to produce a useful output?

 

Depends on size/ number of panels (watts).

 

Cheers.

[mango]

Solar panels don't run at 12/23/14 volts but 18/22.5 hence the need for the itermediary controller the more expensive of which MPPT are converters with some wizadry to give you 25% more than the cheaper MPW ones.

 

Folk will recommend 'quality' branded ones at price beyond that which I would pay. Cheapo Chinese ones on EBay or even second hand ones will do the job at about 0.50p per watt.

 

I used to reckon that two 55 watt panels ran my old fridge in the summer; No need for it in the winter.

 

Considerations are how much roof space you want to give them and what pay back time you are aiming for. I prefer panels up to 100 watt, 12v nominal, that I have added too over time and, that I can hop scotch over when single handing at locks etc.

 

There are lots of other considerations but not worth getting in to if you are just trying to obviate the fridge load using the batts

Thanks very much for that. I did not mention that I'm collecting information from a friend who has a good collection of mushroom vents on the roof of his boat and probably will be single-handing.

[smileypete]

Best thing for limited NB roof space is the camping/RV type 18V panels, can be had from Ebay for about 80p/watt last time I looked.

 

If only a small amount of solar is needed maybe pair them up with a reasonable PMW controller like a 'Landstar' PWM solar controller from the likes of Amazon or Ebay.

 

But if lots of solar is needed and roof space is rather limited, go for a MPPT like a 'Tracer' from the likes of Bimble Solar.

 

cheers, Pete.

~smpt~

[junior]

Best thing for limited NB roof space is the camping/RV type 18V panels, can be had from Ebay for about 80p/watt last time I looked.

 

If only a small amount of solar is needed maybe pair them up with a reasonable PMW controller like a 'Landstar' PWM solar controller from the likes of Amazon or Ebay.

 

But if lots of solar is needed and roof space is rather limited, go for a MPPT like a 'Tracer' from the likes of Bimble Solar.

 

cheers, Pete.

~smpt~

Next time you 'look', could you put a link on here? I've spent the afternoon looking at solar panels and I'm still none the wise.

[BD3Bill]

I agree with Pete

 

If you're on eBay look for Photonic Universe, My 40w PMW kit cost £109 and is pukka. Runs our small fridge fine.

 

Not connected to this firm myself BTW.

 

They sent us a replacement FOC when the one we ordered got lost in the post. Good customer service & value.

 

Cheers Bill

[smileypete]

Next time you 'look', could you put a link on here? I've spent the afternoon looking at solar panels and I'm still none the wise.

 

Try searching on 'solar (75w, 80w, 90w, 100w, 120w, 125w)' with Ebay UK and sort by best match it should turn up quite a few. Then narrow down by category and price, and sort by price incl. shipping to pick out some more. But it looks like they're a little dearer now and start around £1/watt these days

 

If you're buying a PWM controller the current capability must be higher than the max current output of the panels. If buying a MPPT the power capability should be more than the max power output of the panels, but if it's a bit less it will likely be OK.

 

The panels aren't so much of a problem, but the cheaper controllers can be a mixed bag, best go for the ones I mentioned, the Tracer ones have a good reputation on here.

 

If your're near Matty40 I think he installs solar for people, maybe worth a pm to him.

 

cheers, Pete.

~smpt~

Edited September 1, 2013 by smileypete

[junior]

 

Try searching on 'solar (75w, 80w, 90w, 100w, 120w, 125w)' with Ebay UK and sort by best match it should turn up quite a few. Then narrow down by category and price, and sort by price incl. shipping to pick out some more. But it looks like they're a little dearer now and start around £1/watt these days

 

If you're buying a PWM controller the current capability must be higher than the max current output of the panels. If buying a MPPT the power capability should be more than the max power output of the panels, but if it's a bit less it will likely be OK.

 

The panels aren't so much of a problem, but the cheaper controllers can be a mixed bag, best go for the ones I mentioned, the Tracer ones have a good reputation on here.

 

If your're near Matty40 I think he installs solar for people, maybe worth a pm to him.

 

cheers, Pete.

~smpt~

 

Already got a Tracer 30A MPPT controller on the way, it was just the solar panels themselves i was having problems with. So many to choose from on eBay at wildly varying prices got me to a stage where i was worried i was going to waste £300 and then find out i'd bought the wrong thing.

 

I'm going to order 2 of the 100w Semi-flexible panels @ £150 each. I know somebody highlighted on my other thread that they didn't give the best output, but on the basis that they are for long term battery maintenance rather than as a real time power supply, i think they will do what i want.